Pressure-sensitive adhesives based on epihalohydrin polymer and polyketone resins

ABSTRACT

PRESSURE-SENSITIVE SOLVENT RESISTANT ADHESIVES ARE DISCLOSED WHICH CONSISTS ESSENTIALLY OF AN EPIHALOHYDRIN POLYMER AND A THERMOPLASTIC POLYKETONE RESIN COMPRISING THE CONDENSATION PRODUCT OF AN ALIPHATIC KETONE HAVING A TOTAL OF 3 TO 6 CARBON ATOMS; A MONOARYL ALKYL KETONE HAVING FROM 6 TO 10 RING CARBON ATOMS IN THE ARYL GROUP AND FROM 1 TO 4 CARBON ATOMS IN THE ALKYL GROUP; AND ALIPHATIC KETONE HAVING A TOTAL OF 3 TO 6 CARBON ATOMS WITH A LOWER ALIPHATIC ALDEHYDE, A MONOARYL ALKYL KETONE HAVING FROM 6 TO 10 RING CARBON ATOMS IN THE ARYL GROUP AND FROM 1 TO 4 CARBON ATOMS IN THE ALKYL GROUP WITH A LOWER ALIPHATIC ALDEHYDE; OR A CARBOCYCLIC KETONE HAVING 3 TO 7 RING CARBON ATOMS WITH A LOWER ALIPHATIC ALDEHYDE.

United States Patent PRESSURE-SENSITIVE ADHESIVES BASED ON EPIHALOHYDRINPOLYMER AND POLY- KETONE RESINS Robert H. Hackhel, Lombard, Ill.,assignor to The Kendall Company, Walpole, Mass.

'No Drawing. Filed Dec. 6,1971, Ser. No. 205,284

' Int. Cl. 008g 37/38 US. Cl. 260-828 9 Claims ABSTRACT OF THEDISCLOSURE Pressure-sensitive solvent resistant adhesives are disclosedwhich consist essentially of an epihalohydrin polymer and athermoplastic polyketone resin comprising the condensation product of analiphatic ketone having a total of 3 to 6 carbon atoms; a monoaryl alkylketone having from 6 to ring carbon atoms in the aryl group and from 1to 4 carbon atoms in the alkyl group; and aliphatic ketone having atotal of 3 to 6 carbon atoms with a lower aliphatic aldehyde; a monoarylalkyl ketone having from 6 to 10 ring carbon atoms in the aryl group andfrom 1 to 4 carbon atoms in the alkyl group with a lower aliphaticaldehyde; or a carbocyclic ketone having 3 to 7 ring carbon atoms with alower aliphatic aldehyde.

' This invention relates to pressure-sensitive, oil and aliphatichydrocarbon solvent resistant adhesives and more particularly topressure-sensitive adhesives containing an epihalohydrin polymer and aselected polyketone resin.

The development of a pressure-sensitive adhesive having a minimum numberof components and good resistance to oil andaliphatic hydrocarbonsolvents has been a long sought for objective of the pressure-sensitivetape industry. While such rubbers as chloroprene have some solventresistant properties, they must be cured to achieve operable solventresistance, but this property is realized at the expense of pressuresensitivity. Solvent resistant adhesives based on nitrile rubbers havealso been disclosed, for example, in US. Pat. 2,601,016, but largeamounts of plasticizer are required to produce an adhesive havingsufficient tack. In addition to an economical and manufacturingdisadvantage, the use of a plasticizer is unattractive in that such anadditive is migratory and tends to weaken the cohesive strength of theadhesive.

Now it has been found in accordance with this invention that apressure-sensitive adhesive having excellent oil and aliphatic solventresistance can be formulated by blending:

(a) An elastomeric epihalohydrin polymer comprising recurring unitshaving the formula wherein X is halogen, e.g; chlorine or bromine, and nis zero to 2; and

- (b) A thermoplastic polyketone resin comprising the condensationproduct of an aliphatic ketone having a total of 3 to 6 carbon atoms; amonoaryl alkyl ketone having from -6 to 10 ring carbon atoms in the arylgroup and from 1 to 4 carbon atoms in the alkyl group; an aliphaticketone 3,808,288 Patented Apr. 30, 1974 having a total of 3 to 6 carbonatoms with a lower aliphatic aldehyde; a monoaryl alkyl ketone havingfrom 6 to 10 ring carbon atoms in the aryl group and from 1 to 4 carbonatoms in the alkyl group with a lower aliphatic aldehyde; or acarbocyclic ketone having 3 to 7 ring carbon atoms with a loweraliphatic aldehyde; said thermoplastic polyketone resin being present inan amount from about 30 to about 150 parts per parts of saidepihalohydrin polymer.

Furthermore, the pressure-sensitive adhesive compositions of thisinvention do not require the use of a plasticizer, and thus are stable,easy to manufacture and economical.

Exemplary epihalohydrin polymers (a) suitable for use in thepressure-sensitive adhesive compositions disclosed herein are Hydrin 100and Hydrin 200, products of the B. F. Goodrich Chemical Company. Hydrin100 elastomer comprises units corresponding to Formula I wherein X ischlorine and n is 0, and has a specific gravity of 1.36. Chlorineanalysis has indicated that Hydrin 200 comprises units corresponding toFormula I wherein X is chlorine and n is about 1.4; it has a reportedspecific gravity of 1.27. However, the aforementioned epihalohydrinpolymers are merely illustrative, and other polymers having the FormulaI can be suitably employed.

As previously mentioned, various thermoplastic polyketone resins aresuitable for use in the compositions of this invention. Illustrative ofthe condensation products of aliphatic ketones having a total of 3 to 6carbon atoms are the condensation products of acetone, methyl ethylketone, 3-hexanone, etc. Exemplary condensation products of monoarylalkyl ketones having from 6 to 10 ring carbon atoms in the aryl groupand from 1 to 4 carbon atoms in the alkyl group are acetophenone,propiophenone, butyro phenone, valerophenone, 1-butyronaphthone, etc.Suitable for use are condensation products of the aforementionedaliphatic ketones and monoaryl alkyl ketones with lower aliphaticaldehydes; by the term lower aliphatic aldehyde in the claims andspecification herein is meant an aldehyde having a total of 1 to 4carbon atoms. Exemplificative of this class of thermoplastic polyketoneresins are the condensation products of acetone and butyraldehyde,methyl ethyl ketone and formaldehyde, acetophenone and formaldehyde,1'-butyronaphthone and formaldehyde. Typical of the condensationproducts of a carbocyclic ketone having 3 to 7 ring carbon atoms with alower aliphatic aldehyde are the condensation products of cyclopropanoneand butyraldehyde, cyclohexanone and formaldehyde,2,5-eyclohexadien-1-one and formaldehyde, and cycloheptanone andformaldehyde. Mixtures of any of the aforementioned condensationproducts can also be employed.

While any of the previously described thermoplastic polyketone resinscan be utilized in the practice of this invention, it is preferred toemploy the condensation prod specification herein is meant to includeboth the condensation products of acetophenone and the condensationproducts of acetophenone with a lower aliphatic aldehyde, such asformaldehyde.

Although the thermoplastic polyketone resins can be employed in theadhesive compositions of this invention in the aforementionedproportions, preferred embodiments comprise per 100 parts ofepihalohydrin polymer, 30 to 120 parts of the condensation product of analiphatic or monoaryl alkyl ketone, and 30 to 100 parts of thecondensation products of aliphatic, monoaryl alkyl and carbocyclicketones with lower aliphatic aldehydes.

Optional minor additives can be added to the adhesive compositions ofthis invention, in amounts which do not materially adversely effecttheir use as oil and aliphatic solvent resistant pressure-sensitiveadhesives. Exemplary additives include high temperature stabilizers andanti oxidants; fillers such as hydrated silica, talc, alumina, antimonyoxide, etc.; plasticizers such as N-ethyltoluene sulfonamide; flameretardant agents such as tris 2,3-dibromopropyl phosphate, etc. However,it is a feature of these compositions that additives are not necessaryto produce the desired properties.

In the preparation of pressure-sensitive adhesive tapes, thecompositions of this invention are applied to appropriateself-supporting flexible backings by conventional techniques such ascasting, transfer coating, calendering, etc. Suitable flexible backingsinclude polyester films, e.g. polyethylene terephthalate and tensilizedpolyethylene terephthalate; polyvinyl chloride films; polyvinyl fluoridefilms; polyvinylidene chloride films; polyimide films, e.g. those madefrom the polycondensation of an aromatic tetrabasic acid and an aromaticdiamine; polyvinylidene fluoride films; aluminum foil; cloth; laminatesof the aforementioned films with cloth; glass cloth; non-wovenmaterials; paper; strand-reinforced paper; etc. If desired, an adhesivepriming coat may be applied to the flexible backing prior to coatingwith the pressure-sensitive adhesive composition, but this is notessential to the preparation of excellent adhesive tapes.

In the following examples, a Polyken Probe Tack Tester was used indetermining the probe tack. This apparatus, which is fully described inUS. Pat. 3,214,971, consists of four functional parts: (1) a 304stainless steel cylindrical probe, 0.50 cm. in diameter, machined at oneend at 90 to the longitudinal axis, and finished to a surface roughnessof to 20 microinches RMS; attached to the compression loaded spring of(2) a series L Hunter Mechanical Force Gage (Hunter Spring Company,Brochure 750/FG, revised February 1961), (3) an annulus having anopening slightly larger than the diameter of the probe and (4) a carrierfor the annulus which moves down to bring the annulus around the probeand then up to remove the annulus therefrom. The procedure described inthe aforementioned 971 patent was followed, employing a carrier speed ofl cm./sec.; a contact time of one second and a loading of 100 gms./cm.

The peel adhesion values are the forces required to remove an adhesivetape from a stainless steel surface after contact therewith for 2minutes at a temperature of about 75 F. The tape was stripped from thesurface at a 180 angle using a crosshead speed of 12 inches per minuteaccording to ASTM Test Method D-l000.

A Rolling ball tack was determined by securing a piece of the adhesivetape, adhesive side up, to a horizontal surface. A steel ball /2 inch indiameter is placed on a track, inclined 30 to the horizontal testsurface; the distance in inches along the inclined plane is the firstreported value. The ball is released, and allowed to roll to a stop onthe adhesive. The distance in inches traveled on the adhesive isreported as the second measurement Solvent resistance was determinedfollowing the procedure described in ASTM Test Method D-1000, ShearStrength After Solvent Immersion, Adhesive to Adhesive, w t qut u g f headhesi e 29m.

EXAMPLE 1 An epichlorohydrin-ethylene oxide copolymer elastomer (Hydrin200, marketed by B. F. Goodrich Chemical Co.) was milled for about 3minutes on a two-roll mill, each roll having a length of 12 inches and adiameter of 6 inches, with the rolls turning at differential speeds.Fifty grams of milled elastomer, 15.0 g. of Polyketone Resin ZKRA-0252(a resin marketed by Union Carbide Corporation, which infrared analysisindicates is an acetophenone resin) and 240.0 g. of methyl ethyl ketonewere weighed into a 1 quart friction lid can which was sealed and placedon a rolling mill for three days. The resulting composition was smoothin texture, viscous, and cream in color. It was spread onto a 2.2 milthick polyethylene terephthalate film and dried at about C. for about 4minutes. The dried pressure-sensitive adhesive layer was 1.4 mils thick.The physical and chemical properties of the adhesive tape are set forthin the table. I

EXAMPLES 2-4 "In Examples 2-4 the procedure and ingredients of Example 1were employed, varying only the amount of Polyketone Resin ZKRA-0252.Utilizing 25.0, 35.0 and 50.0 grams respectively of the resin, tapeshaving a dry adhesive thickness of 1.4, 2.1 and 2.0 mils were prepared.The properties of the pressure-sensitive ad hesive tapes are reported inthe table.

EXAMPLE 5 Following the procedure of the previous examples, an adhesivecomposition was prepared from 50.0 g. of Hydrin 200 elastomer and 35.0g. of Polyketone Resin ZKMA-OZS 1, a resin marketed by Union CarbideCorporation, which evidence indicates is a methyl ethyl ketone:formaldehyde resin, in 240.0 g. of methyl ethyl ketone. After spreadingand drying on 2.2 mil thick polyethylene terephthalate film, a dryadhesive thickness of 1.9 mils was measured. The properties of thepressure-sensitive adhesive tape are given in the table.

EXAMPLE 6 EXAMPLES 7-8 Following the procedure of the previous examples,adhesive compositions were prepared from 50.0 g. of milled Hydrin 200and different amounts of a cyclohexanoneformaldehyde resin (PolyketoneA, marketed by BASF Corporation) in 240.0 g. of methyl ethyl ketone.Twenty grams of resin were used in Example 7 and 35.0 g. in Example '8.After spreading and drying as in Examples 1-6, adhesive thicknesses of1.8 mils and 1.9 mils respec: tively were measured. The properties ofthe adhesive tapes are listed in the table.

EXAMPLE 9 Five hundred grams of Hydrin 200 elastomer was milled as inExample 1 but employing mill roll temperatures of 200 to 220 F. Theamount of 0.5 g. of polymerized trimethyl dihydroquinoline (AgeriteResin D, sold by R. T. Vanderbilt Co.) was added as a high temperaturestabilizer and antioxidant. Then 350.0 g. of .Polyketone Resin ZKRA-0252was added slowly, withmixing, to the milled elastomer, over a period ofabout 15 minutes. The resulting adhesi e c p tion. he ted on the mill toabout 300-330" F. and melt applied following the procedure described inU.S. Pat. 2,879,547, onto the cloth side of a polyethylene clothlaminate to a thickness of 3.3 mils. The properties of thepressure-sensitive 3. The pressure-sensitive adhesive of claim 2 whereinsaid epihalohydrin polymer is a copolymer of epihalohydrin and ethyleneoxide.

4. The pressure-sensitive adhesive of claim 3 wherein adhesive tape arereported in the table. 5 said thermoplastic polyketone resin is anacetophenone TABLE What is claimed is: resin, and said resin is presentin an amount from about 1. A pressure-sensitive adhesive consistingessentially 30 to about 120 parts per 100 parts of said epihalohydrin ofpolymer.

(a) an elastomeric epihalohydrin polymer comprising 5. Thepressure-sensitive adhesive of claim 4 wherein recurring units havingthe formula said acetophenone resin is the condensation product ofacetophenone with formaldehyde. L 6. The pressure-sensitive adhesive ofclaim 3 wherein said thermoplastic polyketone resin is the condensationCHIX product of methyl ethyl ketone and formaldehyde, and said resin ispresent in an amount from about 30 to about whzelrlelln X is chlorine orbromine and n is zero to 2, 10(7) h per 100 parts. 9 h epihalohy 1polynfien m in the 0 e pressure-sensitive a esive of c aim 3 w erein201;31 :2 85 323112? zir i lipli al ic l et r rb hiving saldthermoplastic polyketone resin 1s the condensation a total of 3 to 6carbon atoms; a monoaryl alkyl product of cyclohexanone and formaldehydeand said ketone having from 6 to 10 ring carbon atoms in the resm lspresent m an amfmnt .from abollt to about 100 aryl group and from 1 to 4carbon atoms in the alkyl 30 Parts Per 100 Parts of eplhalqhydrm lgroup; an aliphatic ketone having a total of 3 to 6 hPresSur.e'SenS1tlve zildheswe clam 2.Wherem carbon atoms with a loweraliphatic aldehyde; a Sald eplhalohydnn f polyeplchlorqhydrm' monoarylalkyl ketone having from 6 to 10 ring cap 9. The pressure-sensitiveadheslve of claim 8 wherein bon atoms in the aryl group and from 1 to 4carbon Salli thermoPlasnc. pplyketone .resm Is an acetophenone atoms inthe alkyl group with a lower aliphatic alde- 35 T651 and Sald resm ispresent m an amqunt i abollt hyde; or a carbocyclic ketone having 3 to 7ring cap 30 to about 120 parts per 100 parts of said epihalohydrln bonatoms with a lower aliphatic aldehyde; polymer d said thermoplasticpolyketone resin being present in an References amount from about 30 toabout 150 parts per 100 parts 40 UNITED STATES PATENTS of saidepihalohydrm po ym 2,699,431 I/ 1955 Harvey 260828 2. Thepressure-sensitive adheslvc of 0131111 1 wh e 3 11 ,851 1/19 4 Harveysaid thermoplastic polyketone resln is the condensation 3,310,504 5/1967 Vandenberg 260 823 product of a phenyl alkyl ketone having 1 to 4carbon atoms in the alkyl group; the condensation product of an FOREIGNPATENTS aliphatic ketone having a total of 3 to 6 carbon atoms 1,038,2398/1966 Great Britain. with a lower aliphatic aldehyde; the condensationproduct of a phenyl alkyl ketone having 1 to 4 carbon atoms PAULLIEBERMAN, Primary Examiner in the alkyl group with a lower aliphaticaldehyde; or the condensation product of cyclohexanone with a loweraliphatic aldehyde.

117-122 PF; 26030.6 R, 30.8 R, 37 AL, 37 R, 823

